1.Field of the Invention
The present invention relates to a friction clutch.
2.Discussion of the Prior Art
From German reference 44 14 033 A1, a friction clutch is known that has a clutch housing which is ordinarily provided on a flywheel mass. With the clutch housing there is associated a pressing means, in the form of a diaphragm spring, for a pressing plate which is provided in order to apply pressure to one side of a clutch disk. The opposite side of the clutch disk rests, in customary manner, against a counter pressure surface. The radially inner ends of the pressing means are functionally connected with the disengagement bearing of a disengager which may be constructed in accordance with German reference 44 07 665 A1. With such a disengager, which operates hydraulically, when a piston is acted on by pressure, it is moved out in the direction towards the pressing means. The pressing means is thus deformed and thereby functionally connected to or disconnected from the clutch disk via the pressing plate.
These friction clutches have the disadvantage that for each retraction or extension, the pressing means must always be considerably changed with respect to its state of deformation and/or in its position, which, insofar as the pressing means is a diaphragm spring, always goes hand in hand with a change in the tension thereof. Upon this deformation of the pressing means, considerable work must be applied via the disengager. Since the disengager must generally be operated by the driver by means of a foot pedal, the driver must either apply a high actuating force or corresponding step-up means must be provided in the engagement or disengagement path, which has a detrimental effect on the disengagement path within the friction clutch. This problem can be further increased in case of wear by the fact that the pedal forces to be applied by the driver can further increase as a result of the wear curve of a diaphragm spring. Accordingly, if the driver is to be spared this, an expensive wear compensation must be provided, which is either arranged in the friction clutch and acts mechanically in accordance with the wear compensation described in German reference 42 39 289 A1, or else a hydraulic wear compensation is provided within the disengagement system. Viewed as a whole, the force to be applied by the driver may be maintained somewhat constant by these measures, but the high technical expense and the deformation work which must nevertheless be performed on the pressing means remains.